There are 2.1 million children 0-15 years of age living with HIV worldwide; the vast majority were perinatally HIV-infected (PHIV), reside in resource limited low-and-middle income countries (LMICs), and are surviving into adolescence and young adulthood. In Thailand, where the proposed study will take place, there are over 14,000 children under 15 living with HIV, and tens of thousands of perinatally HIV-infected (PHIV) adolescents and young adults. PHIV youth must contend with the negative effects of life-long viral infection and chronic inflammation on their neurodevelopment, medical status, mental health, and, for many, the demands of lifelong ART adherence ? placing them at risk for not achieving these important milestones. Neurocognitive impairment (NCI) is chief among these negative effects. NCI in PHIV youth most commonly affects the neurocognitive domains of working memory, executive function and processing speed. NCI can affect youth?s ability to perform in and complete school, interact successfully with peers and adults, find employment, initiate and maintain long-term relationships, and function independently. NCI can also interfere with adherence to medication, which is critical in HIV, and increase poor decision-making and greater HIV transmission risk behaviors (e.g., unprotected sex). The first step in addressing NCI in PHIV youth is detecting and diagnosing it, but doing so in Thailand faces numerous challenges. Few neurocognitive screening tests exist for Thai PHIV youth. The tests that do exist require highly trained personnel to administer and score, take several hours to administer, and many suffer from cultural biases because they were developed for and normed on youth in the US or Europe. Without accurate, clinically useful, and relatively brief NCI assessments that can be accurately administered by all levels of clinical staff, PHIV youth in Thailand will not be assessed, missing opportunities to detect NCI and intervene. NeuroScreen is a brief, easy-to-use app for Android devices to assess for NCI that is designed to be administered by all levels of clinical staff. The app contains ten neurocognitive tests assessing processing speed, executive functions, working memory, verbal memory, and motor speed. It is standardized and highly automated, requires minimal training to administer, and does not require record-keeping or scoring. The proposed study will: (1) adapt NeuroScreen for Thailand and Thai-speaking populations of PHIV youth; (2) generate preliminary estimates of the adapted tests? validity indicators; (3) examine the adapted NeuroScreen?s usability and acceptability among PHIV Thai youth and clinical staff; and (4) explore associations between NeuroScreen performance and medical (viral load), behavioral health, ART adherence, and neuroimaging outcomes. These data will be the basis for future larger-scale research on validation, implementation and scale-up of this mobile health tool for use in Thailand and other LMICs. NeuroScreen could be easily modified for use in other diseases and LMICs that rely on task-shifting due to limited healthcare resources.